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0 viewsTwo million Ventilated Improved Pit Latrines (VIPLs) have been created in South Africa since the early 1990s. As they become full and unusable, VIPLs pose serious health and environmental threats to communities.
The e’Thekwini Municipality is leading the race to solve this impending crisis. Durban has become the first city in Africa to test the effective disposal of pit latrine faecal sludge through a locally-patented technology that sanitises and reforms the matter as pellet soil fertiliser.
Thirty-five thousand pit latrines, mainly located in informal settlements around Durban have been emptied since the project’s inception in 2010. 240 people have been employed to provide this service and they have also started emptying school pit latrines. e’Thekwini officials closely monitor the health and safety of workers who are trained to adhere to standards. Workers undergo regular full medical examinations (those vulnerable to disease are not employed) and have compulsory hot water showers at the end of each day.
After workers collect the sludge, reception tanks are emptied into the Latrine Dehydration and Pasteurisation (LaPeDa) Machine housed inside a mobile shipping container. The sludge is pumped into a large turning rotor screw that forces the contents through a small, metal filter that removes all moisture from the contents. Any material not able to pass through the small holes of the filter is ejected as detritus, which is then processed to remove any health hazards and disposed.
The drier waste material, which emerges as thin spaghetti-like noodles from the filter, is transported onto a porous conveyer belt that further drains any remaining liquid. The ‘noodles’ are fed into a drying machine for about six minutes which transforms them into pellets devoid of any water content. These pellets are directly sent into a second machine where they are sterilized with medium wave infrared radiation rays to destroy all pathogens or any health threatening elements. The dried, pasteurised, and by now breaking pellets with a greyish charcoal-like colour, get fed into plastic bags that are weighed and sealed.
The pellets have a very high fertiliser value. e’Thekwini distributes the pellet fertilizer to community food gardens like those of Luganda Primary School in Durban. Luganda is one of few schools in South Africa to tend a community garden with this pellet fertiliser. The University of KwaZulu-Natal is conducting scientific tests on these gardens, which demonstrate beneficial impact on plant growth and could further demonstrate a long-term impact in enriching the soil. When these pellets are used in gardens, spinach appears to grow up to a third more in height than when a conventional fertilizer is used. Where normally an aubergine plant produces three or four aubergines, when this pellet fertiliser is used, up to a dozen aubergines can grow on one plant.
This is an innovation of global importance. The chief e’Thekwini engineer behind the project recently won an international award in 2011. Both Brazil and Kenya are now involved in serious discussions with the e’Thekwini Municipality to apply this project to their context. Bill Gates is studying the patented designs and his Foundation is engaging the best engineers around the world to design the machinery needed to implement similar projects in other countries on a far larger scale.
This project won the Gold Award and R40 000 at the Impumelelo Social Innovations Centre Awards ceremony, and has peaked the interest of the Bill Gates Foundation, which hopes to design the machinery so implement this project in other countries.
Image 1: Pellets made from the LaDePa technology
Image 2: Planting a garden with the pellets